New on the market, the Metallic Sharpie is a vast improvement over other metallic pens out there -- no shaking the pen before use, and the ink doesn't puddle up. It dries permanent and shows up great on dark
surfaces as well as light ones. It became favorite art tool in my arsenal when I was able to write a friends phone number on a freshly opened, ice-cold beer bottle. Seconds after jotting the number, it was indelible. I try to take it everywhere -- it's good for men's room graffiti, VHS tapes, I even labeled various keys on my key ring. You can get metallic sharpies at Staples or Office Max.
--Chris Sperandio

There's almost no other way to easily write on slippery surfaces. The metallic sharpie uses silver ink, which has remarkable contrast against both light and dark surfaces. For writing on black plastic or enamel (there is more of it around than you think) nothing else will do.
--KK

Metallic Sharpie
$3
(2 pk.)
From Amazon, or where pens are sold